Drug & supplement interaction

Dhea + Fexofenadine

Fexofenadine brand name: Allegra.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Dhea has a moderate interaction with Fexofenadine. Theoretically, DHEA might increase the levels of drugs metabolized by CYP3A4.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Dhea and Fexofenadine

Here is the interaction we found between these two, with the evidence behind it.

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Fexofenadine

Fexofenadine falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Dhea interacts with.

Theoretically, DHEA might increase the levels of drugs metabolized by CYP3A4.
Some preliminary evidence shows that DHEA may inhibit CYP3A4; however, the clinical significance of this potential interaction is not known.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the honest take on pairing DHEA with Allegra (fexofenadine): the worry on file is that DHEA might block an enzyme called CYP3A4, which could let some medications build up. The thing is, fexofenadine barely relies on CYP3A4 to be cleared. It's mostly moved through the body unchanged by transporters rather than chewed up by that enzyme, so this particular concern doesn't fit it very well.

On top of that, the evidence here is purely theoretical and anecdotal, not something proven in real patients. Even if levels nudged up slightly, fexofenadine is a non-drowsy antihistamine and is generally very gentle, so a big problem is unlikely. Still, if you're considering DHEA, run it past your pharmacist or doctor, mainly because DHEA is a hormone with its own effects.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Frye RF, Kroboth PD, Folan MM, et al. Effect of DHEA on CYP3A-mediated metabolism of triazolam. Clin Pharmacol Ther 2000;67:109 (abstract PI-82).

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Dhea Also Interacts With Other Medications

Dhea has 767 moderate, 8 minor known drug interactions in our database — the Fexofenadine one above is one of them. If you take anything else, check it against the full list below.

Moderate 767 Minor 8 No known interaction 2,055 (incl. Fexofenadine)
Taking anything else?

Check Another of Your Medications Against Dhea

Covers the 2,830 medications we’ve checked against Dhea. Pick one to open its full report.

From our Q&A

Questions About Dhea or Fexofenadine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Dhea or Fexofenadine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Fexofenadine

This page covers Dhea only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fexofenadine page lists 154 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Apple (major), Grapefruit (major), St. John's Wort (major) and Sweet Orange (major).

By severity: 5 major · 111 moderate · 38 minor.

From our pharmacist’s overview on the Fexofenadine page

“An over-the-counter allergy pill sounds like the last place serious interactions would hide, but fexofenadine (Allegra) has 154 supplements and foods on file, and the five rated major deserve real attention before you combine it with much of anything else. Two of those five sit in most refrigerators.”

Reviewed by 2 · Jul 18, 2026

Open the Fexofenadine interaction page

One more smart check

Taking Dhea as Part of a Dietary Supplement Product? Check It for Interactions

We hold 945 real supplement products containing Dhea, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Dhea. Your product may carry other ingredients that interact with Fexofenadine too, on top of Dhea — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Dhea and Fexofenadine Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Dhea
Top 25%

#239 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Fexofenadine
Steady interest

#1,451 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Dhea

What is Dhea?

Dhea
  • Anti-aging and low DHEA levels
  • Mood and depression
  • Vaginal dryness and sexual health
  • Fertility support
  • Muscle mass and athletic performance
  • Adrenal insufficiency

DHEA is a natural hormone that the body makes and that declines with age, and it is sold as a supplement claiming many benefits. The evidence is mixed and limited for most uses, and because it acts as a hormone it can cause real side effects. Talk to a pharmacist or doctor before using it, especially if you have a hormone-sensitive condition.

Read the full Dhea monograph & all interactions
Medication

About Fexofenadine

What Is Fexofenadine Used For?

Brand name: Allegra

Fexofenadine temporarily relieves symptoms of hay fever (seasonal allergic rhinitis) and other upper respiratory allergies, including runny nose, sneezing, itchy or watery eyes, and itching of the nose or throat.

Several products — including Allegra Hives 24hr tablets — are specifically used to reduce hives (urticaria) and relieve the itching that comes with them. Keep in mind that fexofenadine will not prevent hives or stop an allergic skin reaction from happening in the first place.

See full Fexofenadine drug information
Keep checking

Other Drugs & Dhea

Browse every other medication we’ve checked against Dhea — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
767Moderate
8Minor
2,054No known interaction
767 Moderate 8 Minor 2,054 No interaction
Moderate

767 interactions

Showing 60 of 767 moderate interactions — see all 767 on the Dhea page.

Minor

8 interactions

No interaction 2,054 drugs checked — show the list

We also checked Dhea against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,054 medications checked with no known interaction — see the full Dhea list.

See the full Dhea interactions page
See every supplement checked against Fexofenadine, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Dhea monograph › Uses, safety, and every drug interaction in one place Fexofenadine supplement interactions › Every supplement checked against Fexofenadine, ranked by severity Fexofenadine drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Dhea and Fexofenadine Together: Common Questions

Can you take Dhea with Fexofenadine?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Dhea and Fexofenadine interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Fexofenadine and Dhea?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.